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CVE-2026-78669
Excessive CPU consumption from repeated initial window changes in net/http
High7.5EPSS 0.85%
- Published
- Updated
- Reserved
- Assigned by
- Go
Description
A malicious HTTP/2 peer can cause excessive CPU consumption in the client or server by opening a large number of streams and then sending many small SETTINGS frames containing SETTINGS_INITIAL_WINDOW_SIZE values.
Timeline
ID reserved
By Go
- 45 days later
· 45 days later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Awaiting Analysis | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.85% · top 42% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
- CWE-405: Asymmetric Resource Consumption (Amplification)
- CWE-405 Asymmetric Resource Consumption (Amplification) (opens in a new tab)All about CWE-405 and its CVEs
Affected products
Go standard library · net/http
- affected < 1.26.9
Go standard library · net/http/internal/http2
- affected 1.27.0-0 – < 1.27.2
golang.org/x/net · golang.org/x/net/http2
- affected < 0.60.0
References (6)
- https://go.dev/cl/847186 (opens in a new tab)
- https://go.dev/cl/847308 (opens in a new tab)
- https://go.dev/issue/81742 (opens in a new tab)
- https://groups.google.com/g/golang-announce/c/U2fTuyDJznI (opens in a new tab)
- https://groups.google.com/g/golang-announce/c/ZPwCyRUuGBs (opens in a new tab)
- https://pkg.go.dev/vuln/GO-2026-6611 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-78669)Record last updated .